Coherent x-ray diffraction experiments have been used to probe the dynamics of the charge density wave (CDW) in the quasi-1D system NbSe(3). The 2k(F) satellite reflection associated with the CDW has been measured with respect to external dc currents, below and above the depinning current. These measurements illustrate for the first time the extensive behavior of a moving electronic crystal: the creep regime, with nucleation of CDW dislocations, the flow regime, with motional ordering, along with phase slippage and the role of strong pinning due to an extrinsic defect.